I'm looking for a 2004/5 Ram 2500 and I would like to know what the difference is between a standard 5.9 and an HO version. Is it just the tune on the ECU or is the motor different internally?

Thank you,
Doug

 

The 305 HO has another set of piston cooling nozzles and a little higher compression plus a couple of other things, I can't remember, over the SO. I think they only had the 325 hp 50 state engine after 04.5 325hp and it got the 3rd injection. The engine tag will show the HP and tell if it's early or late 04. The 325s also got a little bigger turbo.Craig

 

The HO did not have a cat. Some of the SO's I think also came with a smaller rear end.

 

Thanks for the reply's, just what I was looking for.

Doug

 

Mine is a 7-2004 build date, sold as a 2005. It is a HO, with a cat and a 6 speed.